Potentials of Branch Predictors: From Entropy Viewpoints
نویسندگان
چکیده
Predictors essentially predicts the most recent events based on the record of past events, history. It is obvious that prediction performance largely relies on regularity–randomness level of the history. This paper concentrates on extracting effective information out from branch history, and discuss expected performance of branch predictors. For this purpose, this paper introduces entropy point-of-views to quantitative characterization of both program behavior and prediction mechanisms. This paper defines two new entropies independent of prediction methods and other two entropies dependent on predictor organization. These new entropies are useful tools for analyzing upper-bound of prediction performance. This paper shows some evaluation results for typical predictors.
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